Helicobacter pylori VacA and gastric ulcer

Helicobacter pylori Found Guilty of Obstructive Jaundice: A Pediatric Case Report

Pediatric Helicobacter pylori infection represents a small proportion of disease that is otherwise decreasing in the developed world. Typical presentations have been well-described in the literature. We report a 15-year-old male who presented with jaundice, anemia, dark urine, and poorly characterized abdominal pain and was found to have obstructive jaundice secondary to a duodenal ulcer resulting from H. pylori infection. Obstructive jaundice is a seldom reported complication of duodenal ulcer, particularly in children. This report reviews H. pylori infection, outlines complications of peptic ulcer disease, and illustrates the rarity of obstructive jaundice as a presenting sign of duodenal ulcer in children.

Biological characteristics and virulence of Helicobacter pylori

This review summarizes the most recent data on the biological characteristics of Helicobacter pylori (morphological, cultural, biochemical). H. pylori pathogenicity factors promoting colonization, adhesion, biofilm formation, aggression, and cytotoxicity, their contribution to the pathogenesis of diseases as well as the possible relationships with various clinical outcomes are described in detail. The genetic heterogeneity of H. pylori strains which can determine different clinical manifestations and have significance for conducting epidemiological studies is also considered.

[Advances in relationship between gastric disease and polymorphisms in both Helicobacter pylori virulence factors and host genetics]

Helicobacter pylori infection may cause many gastric disease, such as peptic ulcers, chronic atrophic gastritis, gastric mucosa-associated lymphoid tissue lymphoma, and gastric cancer. The different clinical outcomes of Helicobacter pylori infection are related to H. pylori virulence factors and host gene polymorphism. H.pylori had been confirmed to be the class I carcinogen by the World Health Organization and International Agency for Research on Cancer Consensus Group (IARC) in1994. Most severe diseases always occur in the background that certain microbial virulence markers (e.g. cagA, vacA) and susceptible host genetic polymorphisms harboured together. Herein, we reviewed the association with H. pylori-related gastric diseases in relation to diffirent H. pylori types and the host polymorphisms.

Aloe improves gastric ulcer in pylorus-ligated rats

AIM: To investigate the effects of aloe on gastric ulcer in pylorus-ligated rats and to explore potential mechanisms involved.

METHODS: Forty-two Wistar rats were randomly divided into three groups: normal control group, ulcer model group and aloe treatment group. Gastric ulcer was induced in rats by ligating the pylorus. The gastric ulcer index (UI), acidity and pepsin activity of gastric juice, and superoxidatase (SOD) activity and malondialdehyde (MDA) level in gastric mucosa were measured in rats of each group.

RESULTS: Compared with the normal control group, the UI, acidity and pepsin activity of gastric juice, and MDA level were increased (39.2 ± 2.5 vs 0.0; 67.25 mmol/L ± 7.1 mmol/L vs 41.31 mmol/L ± 6.3 mmol/L, t = 7.2256; 171.25 U/mL ± 29.25 U/mL vs 98.34 U/mL ± 21.13 U/mL, t = 5.3453; 0.57 NU/mg•pro ± 0.12 NU/mg•pro vs 0.31 NU/mg•pro ± 0.11 NU/mg•pro, t = 4.2207; all P < 0.01) and SOD activity was decreased (t = 8.2339, P < 0.01) in the ulcer model group. Compared with the ulcer model group, the UI, acidity and pepsin activity of gastric juice, MDA level were decreased (t = 11.7584, 6.4310, 3.0276 and 5.1428, respectively; all P < 0.01) and SOD activity was increased (t = 5.3003, P < 0.01) in the aloe treatment group.

CONCLUSION: Aloe improves gastric ulcer in pylorus-ligated rats possibly by inhibiting lipid peroxidation, gastric acid secretion and pepsin activity.

Helicobacter pylori: a ROS-inducing bacterial species in the stomach

BACKGROUND

Reactive oxygen species (ROS) and reactive nitrogen species (RNS) have been reported to impact gastric inflammation and carcinogenesis. However, the precise mechanism by which Helicobacter pylori induces gastric carcinogenesis is presently unclear.

AIM

This review focuses on H. pylori-induced ROS/RNS production in the host stomach, and its relationship with gastric carcinogenesis.

RESULTS

Activated neutrophils are the main source of ROS/RNS production in the H. pylori-infected stomach, but H. pylori itself also produces ROS. In addition, extensive recent studies have revealed that H. pylori-induced ROS production in gastric epithelial cells might affect gastric epithelial cell signal transduction, resulting in gastric carcinogenesis. Excessive ROS/RNS production in the stomach can damage DNA in gastric epithelial cells, implying its involvement in gastric carcinogenesis.

CONCLUSION

Understanding the molecular mechanism behind H. pylori-induced ROS, and its involvement in gastric carcinogenesis, is important for developing new strategies for gastric cancer chemoprevention.

Culture of Helicobacter pylori and purification of antigen protein

Helicobacter pylori (H. pylori) live in the stomach of human. It is a kind of curve bacteria which can lead to chronic gastritis, peptic ulcer and gastric cancer. Usually, antibiotics are used to treat the patients, but they have a lot of side effects. Milk of milch cow immunized with H. pylori vaccine can prevent and treat the infection of H. pylori without side effects. During the production of immune milk, the basic work is to prepare vaccine. During the preparation of sub-unit vaccine, key is to isolate and purify the antigen protein. In this article, we discuss the culture of H. pylori (solid and liquid culture), the recombinant expression and purification of its antigen protein (urease, VacA, CagA and lipopolysaccharide).

Pathogenesis of Helicobacter pylori infection

The clinical outcome of Helicobacter pylori infection is determined by a complex interaction between the bacterium and the host. The main bacterial factors associated with pathogenicity comprise outer membrane proteins, including BabA, SabA, OipA, AlpA, and AlpB, the vacuolating cytotoxin VacA and the products of cagPAI. The multitude of putative virulence factors makes it extremely difficult to test the contribution of each individual factor. Much effort has been put into identifying the mechanism associated with H. pylori-associated carcinogenesis. Interaction between bacterial factors such as CagA and host signal transduction pathways seems to be critical for mediating cell transformation, cell proliferation, invasion, apoptosis/anti-apoptosis, and angiogenesis. An animal model using the Mongolian gerbil is a useful model for showing gastric pathology due to H. pylori infection which is similar to that in humans and can be used to evaluate virulence factors including CagA, host responses, and environmental factors such as salt intake.

Effect of taurine on gastric ulcer in pylorus-ligated rats

AIM: To explore the effect of taurine on the pylorus ligation-induced gastric ulcer in rats and its mechanism.

METHODS: Rat model of gastric ulcer was made by pylorus ligation method. A total of 45 Wistar rats were randomly and averagely divided into 3 groups: normal control group, ulcer model group and taurine-treated group. Six hours later, all the rats were killed, and the gastric mucosal ulcer index (UI), total acidity of gastric juice, pepsin activity and H+,K+-ATPase activity in parietal cells were measured.

RESULTS: In comparison with the normal control group, the ulcer model group showed an increase in UI (35.3 ± 3.7 vs 0, P < 0.01), total acidity of gastric juice (28.56 ± 3.81 mmol/L vs 20.34 ± 4.40 mmol/L, P < 0.01), pepsin activity [7.58 ±1.58 μg/(mL·min) vs 5.83 ± 1.22 μg/(mL·min), P < 0.01] and H+, K+-ATPase activity of parietal cells (8.86 ± 1.50 U/mg vs 6.95 ± 1.03 U/mg, P < 0.01). However, in the treated group, the gastric mucosal injury was attenuated, and the value of gastric mucosal UI (15.4 ± 3.6 vs 35.3 ± 3.7, P < 0.01), total acidity of gastric juice (19.58 ± 3.68 mmol/L vs 28.56 ± 3.81 mmol/L, P < 0.01), pepsin activity [6.36 ± 1.45 μg/(mL·min) vs 7.58 ± 1.58 μg/(mL·min), P < 0.05] and H+, K+-ATPase activity of parietal cells (7.62 ± 1.46 U/mg vs 8.86 ± 1.50 U/mg, P < 0.05) were decreased significantly as compared with those in the model group.

CONCLUSION: Taurine can alleviate gastric ulcerative injury in pylorus-ligated rats, which may be related to the inhibitory effect of taurine on the secretion of gastric acid and pepsin.